Quick coupler assembly

ABSTRACT

A coupling device primarily for use in attaching trowelling blades to the arms of a cement finishing machine. The coupling allows for ready removal and attachment of the blades, allows for reversal of their position through 180*, and in particular provides a dirt excluding seal around the movable parts of the device. The coupling includes upper and lower parts, one of which has a wall the periphery of which seals against the other part, and the interlocking coupling parts are disposed within this wall thus being protected from ingress of dirt. The interlocking parts include catch elements on the lower part, and a locking bar slidable in the upper part to engage the catch elements and which is also movable by handle operated screw means towards and away from the upper part so that when the catch elements are engaged the two parts can be tightly fastened together by turning the handle to draw the locking bar inwardly towards the upper part.

[ 1 July 11, 1972 [54] QUICK COUPLER ASSEMBLY [72} inventor: Francesco Zochll, l0 Cortina Crescent,

Hamilton. Ontario Canada 221 Filed: DQC.22,|970

2| Appl.No.: 100,576

Harding v "94/45 A Colizza et al ..94/45 A Primary Examiner.lacob L. Nackenoff Attorney-Stevens, Davis, Miller & Mosher ABSTRACT A coupling device primarily for use in attaching trowelling blades to the arms of a cement finishing machine. The coupling allows for ready removal and attachment of the blades. allows for reversal of their position through 180. and in particular provides a dirt excluding seal around the movable parts of the device. The coupling includes upper and lower parts, one of which has a wall the periphery of which seals against the other part, and the interlocking coupling parts are disposed within this wall thus being protected from ingress of dirt. The interlocking parts include catch elements on the lower part, and a locking bar slidable in the upper part to engage the catch elements and which is also movable by handle operated screw means towards and away from the upper part so that when the catch elements are engaged the two pans can be tightly fastened together by turning the handle to draw the locking bar inwardly towards the upper part.

5 China, 4 Drawing figures QUICK COUPLER ASSEMBLY The present invention relates to a two-part coupling device, for coupling and locking together two members. which is particularly suitable for use in a dirty environment, such as for use in attaching trowelling blades to a cement finishing machine.

Cement finishing machines, which are also known as trowelling machines, generally have a centrally mounted engine driving a vertical shaft through reduction gearing, on the lower end of which shaft is mounted a hub carrying three or more radial arms, each of these arms being provided with a trowelling blade. The blades are set at a small pitch angle to the plane of rotation, with their trailing edges lowermost. In operation, the engine causes the blades to move in a circular path in contact with a horizontal cement surface to smooth the surface. Machines of this type are well known, and are described for example in US. Pat. Nos. 2,689,507 to McGrery and 2,983,203 to Fletcher.

The blades of cement finishing machines wear quite rapidly, and so must be easily replaceable. Also, since the blades are inclined to the cement surface, it is primarily the rear portion of the blade which wears, and accordingly the blades can be used for a longer period if the position of these on the radial arms can be reversed through 180, whereby the unwom leading edges then become trailing edges. It is one object of the invention to provide a coupling device for releasably attaching a trowelling blade to the radial arm of a cement finishing machine which allows for quick removal of the blade, and which preferably allows ready reversal of the blade position through 180. The invention also provides a coupling device which is particularly suited to such an application as its operation is not seriously affected by the presence of cement or other dirt or foreign matter, and for this reason coupling devices in accordance with the invention are thought to have applications in other fields where the presence of dirt or foreign matter tends to obstruct the operation of known devices.

The present invention represents an improvement over the device shown in US. Pat. No. 3,402,647, of which l am ajoint inventor. The device shown in this prior patent allows reversal of the blade position through I80. Also, the upper part of the device has an elongated continuous encircling wall formed by the sides and closed ends of a channel member the edges of which are intended to form a seal against the upper surface of the trowelling blade. However I have found that the single seal provided for by this channel member is not sufficient to prevent cement and other foreign material entering into the space within the channel member which houses the interengaging operative parts. This intcrfers with operation of the device to release and to fix blades. Another drawback of this prior arrangement is that, for removal of the blade, the blade has to be tilted relative to the radial arms of the machine, as indicated in FIG. 3 of this prior patent. This necessitates that the machine, which is quite heavy, has to be lifted or at least tilted from the normal rest position before a blade can be replaced.

According to the present invention, in a coupling device comprising two detachable parts, namely an upper part and a lower part, the upper part has a first continuous elongated encircling wall extending towards the lower part to engage the lower part all around the wall periphery, and the lower part has a second continuous elongated encircling wall extending towards the upper part to engage the upper part all around the second wall periphery. The two walls are dimensioned to fit one within the other and each form a seal with the opposed part when the two parts are held together, so as to provide a double sealed enclosure within the walls and between the parts. The device includes interengaging elements within the enclosure comprising two catch elements on the lower part fixed in positions spaced apart longitudinally of said second wall and on opposite sides of the longitudinal center thereof, the interengaging element also including two engaging means carried by a locking member mounted on said upper part for longitudinal movement between a first position in which the engaging means engage both of the catch elements to prevent separation of the two parts, and a second position in which the locking member is disengaged from the catch elements and allows separation of the parts. Screw means extend outwardly from the locking member away from the lower part, passing through an aperture in the upper part, the aperture being dimensioned to allow longitudinal movement of the screw means therein corresponding to movement of the locking member between its first and second positions. A knob or handle means is attached to the screw means and rotatable against a part which limits movement of the knob or handle inwards relative to the upper part. The screw means allows inwards and outwards movement of the locking member relative to the upper part on rotation of the knob or handle means between a loosened position in which the locking member is free to move between its first and second positions and a tightened position in which, with the locking member in its first longitudinal position and engaging the catch elements, the two parts are drawn tightly together and form a double seal around the peripheries of the two walls.

Preferably, the catch elements and locking member are the only means which serve to hold together the upper and lower parts, and with the locking member in its second position the engaging means thereof are out of the path of movement of the catch elements so a to allow the two parts to be separated without any relative sliding or tilting.

In order for the parts to be readily reversed in position through 180, the lower part is preferably provided with two symmetrically placed and similar catch elements, and the locking member is adapted to engage both of these catch elements in sliding from the second to the first positions.

When the invention is used for coupling a trowelling blade to a trowelling machine, the lower part of the device is preferably made integral with the trowelling blade, and the upper part is attached to a radial arm of the machine.

One embodiment of this invention, particularly adapted for use with a cement finishing machine, will now be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 shows a general view of a cement finishing machine, in which coupling devices according to the invention are used,

FIG. 2 shows a sectional elevation through one of the radial arms of the cement finishing machine, showing the coupling device and a part of the trowelling blade, and

FIGS. 3A and 3B show, in combination, an exploded view of the components of the coupling device.

The cement finishing machine shown in FIG. 1 is of generally known type, having a centrally mounted engine 1 driving a rotatable assembly indicated at 2 and including a supporting frame carrying radial arms 4, the radial arms each carrying a trowelling blade 5 attached thereto by a coupling device to be described. The machine is held and controlled by a handle 7, in which are incorporated controls for the engine, and in some cases controls which alter the angle of attack of the trowelling blades. Further details of such machines will be found in the United States patents previously referred to, however a detailed knowledge of such machines is not essential for understanding the present invention.

The present invention will be described with reference to FIGS. 2 and 3, which show details of a coupling device used to attach each trowelling blade 5 of the machine to its radial arm 4. The device includes an upper part 10 attached by bolts 11 to the radial arm 4, and a lower part 12 which is integral with the blade 5. The upper part 10 is shown in exploded view in FIG. 3A, while lower part 12 is shown in FIG. 3B, which is a continuation of the same exploded view.

The lower part 12 will be described first since this is of simple construction, and in particular has no moving parts. This lower part includes the blade 5, which forms its base, and a continuous encircling wall 13 of elongated rectangular form having side wall and end wall portions and 13b and having a flat upper periphery parallel to the blade 5. Two pins 16,

which are parallel to the blade 5, extend transversely between the side wall portions 13a, being welded into holes in the side walls, and forming catch elements for engagement by the upper part. The pins 16 are symmetrically placed one near each end of the side walls 13a, and the whole lower part is in face symmetrical about the longitudinal center of wall 13.

The upper part is in the form of an inverted, elongated rectangular trough, having a top plate 18 and a continuous depending rectangular wall 19 which is sized to fit outside the rectangular wall 13 of the lower part. The periphery of the wall 19 is made flat for sealing engagement with the blade 5 outside the wall 13, and the flat periphery of the wall 13 also seals against the top plate 18 when the wall 19 engages the blade 5. Accordingly, when the two parts are held firmly together the space within the wall 19 is sealed against the ingress of dirt, and the wall 13 provides an additional seal, the two walls providing a double seal against entry of dirt into the enclosure therebetween.

The top plate 18 is provided with three equally spaced tapped holes 21, which receive the bolts 1 l. A guide post 22 is provided fixed to and projecting inwardly from near the center of the top plate. The top plate also has an elongated aperture 23, near to the guide post 22.

A locking member 25, in the form of a bar, is freely slidable within the flange l9, this locking bar having an elongated slot 26 extending through the upper surface thereof and which slides over the guide post 22. The locking bar has at its left hand end a groove 27 sized to engage with one of the pins 16 and constituting a first engaging means, and at its right hand end the locking bar is provided with a recess 28 within a hooklike end portion of the bar, this recess being engageable with the other pin 16 and constituting a second engaging means. The manner of engagement of the locking bar with the pins is best shown in FIG. 2. It will be appreciated from the drawings that the locking bar is adapted to engage both pins simultaneously on sliding from a right hand to a left hand position, and that in the right hand position the engaging means are out of the path of movement of the pins 16 so as to allow the parts to be separated without any relative sliding or tilting being required.

The locking bar 25 is provided with an upwardly extending screwed stud 30, which extends through the aperture 23 and is engaged by the screwed boss 31 of a knob 32. The knob 32 is of rounded triangular shape, intended for easy rotation by a person's fingers. Between the lower end of the boss 31 and the upper surface of arm 4 is provided a washer plate 33 having an aperture for the stud and having turned down flanges 33a slidable along the sides of the arm 4, and which engage these sides to prevent rotation of the plate. The plate 33 also has a cut out portion 33!; providing clearance space around the head of the central bolt ll, so that this bolt does not interfere with the sliding of the plate. Also, it will be seen from FIG. 2 that the radial arm 4 is provided with a slot 4a which accommodates the sliding movements of the stud 30, allowing this to slide freely with the locking bar 25 between positions at which the pins are respectively engaged and disengaged. The boss 31 is rotatable against this plate 33, the plate limiting movement of the boss 31 and knob 32 inwards relative to the upper part.

The final element of the assembly is a guide element 35 in the form of a leaf spring, having a central aperture for the stud 30, and which fits between the underside of top plate 18 and the top of the locking bar 25. This spring is curved so that its center rests against the top plate, and its ends rest against the locking bar, and this spring element serves to keep the locking bar 25 free within trough 10 when knob 32 is loosened, preventing binding and undesirable looseness in the assembly, and also maintains the locking bar roughly parallel with the top plate. The right hand end of the spring element 35 has a central tongue 35a bent down to form a guide element and engageable within the slot 26 of the locking bar, and this prevents the spring element from rotating on the screwed stud and binding in the sides of the walls I9.

In the position shown in FIG. 2, the parts are coupled and locked together, the knob 32 having been tightened in the clockwise direction to draw the locking bar 25 upwards i.e. inwardly relative to the upper part 10), thus sealing the lower periphery of the wall 19 against the trowelling blade, and causing the locking bar recesses to frictionally grip the pins to preventing free sliding movement. To uncouple the device, the knob 32 is turned anti-clockwise, thus freeing the locking bar, and the locking bar is then slid to the right by means of the knob 32, after which the parts can be pulled directly apart and so separated without relative sliding. When the parts are uncoupled, the spring element 35 holds the locking bar in suitable position for re-coupling, which is the reverse of the procedure just described.

The important advantages of the present invention are:

l. The double seal between the periphery of wall 19 and the blade 5, and between the wall 13 and the top plate 18, positively prevents the ingress of dirt into the space in which the locking bar 25 is movable.

2. The parts can be coupled and uncoupled quite easily, and yet can be firmly locked in position when properly coupled. The action of the locking member against the two symmetrical catch elements 16 provides fairly uniform sealing pressure around the periphery of the walls, and this factor also improves the seal which is attained in accordance with this invention.

3. The position of the blade can be reversed through and 4. The parts can be coupled and uncoupled without relative sliding or tilting movement. This is advantageous since a buildup of cement on the parts may cause difficulty in relative sliding movement. Also, unlike with previous designs such as that of US. Pat. No. 3,402,647, there is no need to raise or tilt the machine from the floor in order to release a blade, since this can be released while the machine is still resting on the floor, and resting on the other blade arms.

It will be clear that many different forms of device could be devised which would be within the scope of the present invention. The forms of the locking bar and catch elements could be varied very widely within the scope of the invention, and for example the catch elements might simply be recesses in the lower part, the locking bar having hooks or like portions for engaging in the sides of such recesses. Also, the knob 32 might be replaced with different means, such as a handle, and instead of the knob 32 engaging on a screwed stud, a screwed rod might extend from the knob into a screwed bore in the locking member. Also, means other than the spring element 35 might be used to maintain the locking member in a suitable position. Clearly, numerous other alternatives are possible within the scope of the invention. Last but not least, it will be understood that the terms "upper and lower" part do not refer to definite fixed orientations of the device, but are merely used to identify differing parts of the device.

I claim:

I. A coupling device comprising two detachable parts, namely an upper and a lower part, in which the upper part has a first continuous elongated encircling wall extending towards the lower part to engage the lower part all around the wall periphery, and in which said lower part has a second continuous elongated encircling wall extending towards said upper part to engage said upper part all around the second wall periphery, the two walls being dimensioned to fit one within the other and each forming a seal with the opposed part when the two parts are held together, whereby with the two parts held together a double sealed enclosure is provided within the said walls and between the parts, said device including interengaging elements within said enclosure comprising two catch elements on the lower part fixed in positions spaced apart longitudinally of said second wall and opposite sides of the longitudinal center thereof, said interengaging elements also including two engaging means carried by a locking member mounted on said upper part for longitudinal movement between a first position in which said engaging means engage both of said catch elements to prevent separation of the two parts and a second position in which the locking member is disengaged from the catch elements and allows separation of the parts, screw means extending outwardly from said locking member away from said lower part and passing through an aperture in said upper part, said aperture being dimensioned to allow longitudinal movement of the screw means therein corresponding to movement of the locking member between its first and second positions, and knob or handle means attached to said screw means and rotatable against a part which limits movement of said knob or handle means inwards relative to said upper part, said screw means allowing inwards and outwards movement of the locking member relative to the upper part on rotation of the knob or handle means between a loosened position in which the locking member is free to move between its said first and second positions and a tightened position in which, with the locking member in its first longitudinal position and engaging the catch elements, the two parts are drawn tightly togeflier and form a double seal around the peripheries of said walls.

2. A coupling device according to claim 1 wherein the said catch elements are identical and are symmetrically arranged about the longitudinal center of said second wall, said locking member having engaging means engageable with either of said elements, whereby the relative positions of the upper and lower parts can be reversed through 180".

3. A coupling device according to claim 1, wherein the said catch element and locking member are the only means serving to hold together the upper and lower parts, and wherein with the locking member in its second position the engaging means thereof are out of the path of movement of the catch elements so as to allow the parts to be separated without an( relative sliding or tilting.

4. A coupling device according to claim 1, wherein said locking member in provided with a longitudinal slot extending through the surface thereof furthest from said lower part, and wherein said upper part is provided with a guide post extending towards said lower part into said slot, said post serving to guide said locking member in rectilinear longitudinal movement.

5 A cement finishing machine including rotatable radially extending arms and trowelling blades detachably secured thereto by means of coupling devices each including an upper part and a lower part, said upper part being attached to one of said arms and said lower part being integral with a trowelling blade, in which the upper part has a first continuous elongated encircling wall extending towards the lower part to engage the lower part all around the wall periphery, and in which said lower part has a second continuous elongated encircling wall extending towards said upper part to engage said upper part all around the second wall periphery, the two walls being dimensioned to fit one within the other and each forming a seal with the opposed part when the two parts are held together, whereby with the two parts held together a double sealed enclosure is provided within the said walls and between the parts, said device including interengaging elements within said enclosure comprising two catch elements on the lower part fixed in positions spaced apart longitudinally of said second wall and on opposite sides of the longitudinal center thereof, said interengaging elements also including two engaging means carried by a locking member mounted on said upper part for longitudinal movement between a first position in which said engaging means engage both of said catch elements to prevent separation of the two parts and a second position in which the locking member is disengaged from the catch element and allows separation of the parts, screw means extending outwardly from said locking member away from said lower part and passing through an aperture in said upper part, said aperture being dimensioned to allow longitudinal movement of the screw means therein corresponding to movement of the locking member between its first and second positions, and knob or handle means attached to said screw means and rotatable against a part which limits movement of said knob or handle means inwards relative to said upper part, said screw means allowing inwards and outwards movement of the locking member relative to the upper part on rotation of the knob or handle means between a loosened position in which the locking member is free to move between its said first and second positions and a tightened position in which, with the locking member in its first longitudinal position and engaging the catch elements, the two parts are drawn tightly together and form a double seal around the peripheries of said walls.

I I l l min. man 

1. A coupling device comprising two detachable parts, namely an upper and a lower part, in which the upper part has a first continuous elongated encircling wall extending towards the lower part to engage the lower part all around the wall periphery, and in which said lower part has a second continuous elongated encircling wall extending towards said upper part to engage said upper part all around the second wall periphery, the two walls being dimensioned to fit one within the other and each forming a seal with the opposed part when the two parts are held together, whereby with the two parts held together a double sealed enclosure is provided within the said walls and between the parts, said device including interengaging elements within said enclosure comprising two catch elements on the lower part fixed in positions spaced apart longitudinally of said second wall and opposite sides of the longitudinal center thereof, said interengaging elements also including two engaging means carried by a locking member mounted on said upper part for longitudinal movement between a first position in which said engaging means engage both of said catch elements to prevent separation of the two parts and a second position in which the locking member is disengaged from the catch elements and allows separation of the parts, screw means extending outwardly from said locking member away from said lower part and passing through an aperture in said upper part, said aperture being dimensioned to allow longitudinal movement of the screw means therein corresponding to movement of the locking member between its first and second positions, and knob or handle means attached to said screw means and rotatable against a part which limits movement of said knob or handle means inwards relative to said upper part, said screw means allowing inwards and outwards movement of the locking member relative to the upper part on rotation of the knob or handle means between a loosened position in which the locking member is free to move between its said first and second positions and a tightened position in which, with the locking member in its first longitudinal position and engaging the catch elements, the two parts are drawn tightly together and form a double seal around the peripheries of said walls.
 2. A coupling device according to claim 1 wherein the said catch elements are identical and are symmetrically arranged about the longitudinal center of said second wall, said locking member having engaging means engageable with either of said elements, whereby the relative positions of the upper and lower parts can be reversed through 180*.
 3. A coupling device aCcording to claim 1, wherein the said catch element and locking member are the only means serving to hold together the upper and lower parts, and wherein with the locking member in its second position the engaging means thereof are out of the path of movement of the catch elements so as to allow the parts to be separated without any relative sliding or tilting.
 4. A coupling device according to claim 1, wherein said locking member is provided with a longitudinal slot extending through the surface thereof furthest from said lower part, and wherein said upper part is provided with a guide post extending towards said lower part into said slot, said post serving to guide said locking member in rectilinear longitudinal movement.
 5. A cement finishing machine including rotatable radially extending arms and trowelling blades detachably secured thereto by means of coupling devices each including an upper part and a lower part, said upper part being attached to one of said arms and said lower part being integral with a trowelling blade, in which the upper part has a first continuous elongated encircling wall extending towards the lower part to engage the lower part all around the wall periphery, and in which said lower part has a second continuous elongated encircling wall extending towards said upper part to engage said upper part all around the second wall periphery, the two walls being dimensioned to fit one within the other and each forming a seal with the opposed part when the two parts are held together, whereby with the two parts held together a double sealed enclosure is provided within the said walls and between the parts, said device including interengaging elements within said enclosure comprising two catch elements on the lower part fixed in positions spaced apart longitudinally of said second wall and on opposite sides of the longitudinal center thereof, said interengaging elements also including two engaging means carried by a locking member mounted on said upper part for longitudinal movement between a first position in which said engaging means engage both of said catch elements to prevent separation of the two parts and a second position in which the locking member is disengaged from the catch element and allows separation of the parts, screw means extending outwardly from said locking member away from said lower part and passing through an aperture in said upper part, said aperture being dimensioned to allow longitudinal movement of the screw means therein corresponding to movement of the locking member between its first and second positions, and knob or handle means attached to said screw means and rotatable against a part which limits movement of said knob or handle means inwards relative to said upper part, said screw means allowing inwards and outwards movement of the locking member relative to the upper part on rotation of the knob or handle means between a loosened position in which the locking member is free to move between its said first and second positions and a tightened position in which, with the locking member in its first longitudinal position and engaging the catch elements, the two parts are drawn tightly together and form a double seal around the peripheries of said walls. 